Added firewall.cpp to the process library CMakeLists.
Added firewall.cpp to the process library CMakeLists.

Right now, if you try to build on a non-Windows machine with CMakeLists,
you'll get a linker error claiming that we can't find a symbol from the
process library's firewall.cpp.

This commit simply adds that source file, which fixes the problem.

Review: https://reviews.apache.org/r/37369

abudnik/mesos,gsantovena/mesos,craimbert/mesos,dforsyth/mesos,andschwa/mesos,zmalik/mesos,zmalik/mesos,neilconway/mesos,chhsia0/mesos,yuquanshan/customizedMesos,Gilbert88/mesos,Gilbert88/mesos,asamerh4/mesos,craimbert/mesos,kaysoky/mesos,neilconway/mesos,zmalik/mesos,craimbert/mesos,zmalik/mesos,asamerh4/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,asamerh4/mesos,dforsyth/mesos,jpeach/mesos,kaysoky/mesos,chhsia0/mesos,andschwa/mesos,dforsyth/mesos,kaysoky/mesos,reneploetz/mesos,asamerh4/mesos,verizonlabs/mesos,reneploetz/mesos,gsantovena/mesos,kaysoky/mesos,Gilbert88/mesos,zmalik/mesos,reneploetz/mesos,neilconway/mesos,yuquanshan/customizedMesos,gsantovena/mesos,abudnik/mesos,Aman-Jain-14/customizedMesos,abudnik/mesos,Gilbert88/mesos,verizonlabs/mesos,asamerh4/mesos,Gilbert88/mesos,zmalik/mesos,chhsia0/mesos,gsantovena/mesos,neilconway/mesos,asamerh4/mesos,Gilbert88/mesos,chhsia0/mesos,verizonlabs/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,gsantovena/mesos,craimbert/mesos,Gilbert88/mesos,jpeach/mesos,reneploetz/mesos,asamerh4/mesos,andschwa/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,kaysoky/mesos,andschwa/mesos,kaysoky/mesos,abudnik/mesos,jpeach/mesos,chhsia0/mesos,Aman-Jain-14/customizedMesos,gsantovena/mesos,reneploetz/mesos,jpeach/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,verizonlabs/mesos,chhsia0/mesos,neilconway/mesos,verizonlabs/mesos,yuquanshan/customizedMesos,abudnik/mesos,Aman-Jain-14/customizedMesos,gsantovena/mesos,abudnik/mesos,verizonlabs/mesos,dforsyth/mesos,abudnik/mesos,neilconway/mesos,chhsia0/mesos,neilconway/mesos,craimbert/mesos,kaysoky/mesos,andschwa/mesos,andschwa/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,zmalik/mesos,craimbert/mesos,yuquanshan/customizedMesos,dforsyth/mesos,dforsyth/mesos,yuquanshan/customizedMesos,dforsyth/mesos,craimbert/mesos,andschwa/mesos,yuquanshan/customizedMesos